RESUMO -Foi conduzido um estudo para avaliar o efeito do sistema de cultivo na composição corporal de juvenis de tambaqui e matrinxã, quando cultivados em sistema intensivo, em canal de igarapé, e em sistema semi-intensivo, em viveiros. Foram usados juvenis de tambaqui e matrinxã com comprimento e peso médio inicial de 15,4 cm e 88,3 g e 23,4 cm e 219,4 g, respectivamente. Os juvenis de cada espécie foram estocados a uma densidade de 10 e 1 peixe/m 3 no sistema intensivo e semi-intensivo, respectivamente. O período experimental foi de 170 dias e os peixes foram alimentados duas vezes ao dia, até aparente saciedade, com ração extrusada comercial contendo 30% de proteína bruta. A análise da composição corporal de peixe inteiro e filé de tambaqui e matrinxã demostrou que houve menor deposição de gordura e maior retenção de proteína nos peixes cultivados no sistema intensivo, em canal de igarapé, do que naqueles cultivados no sistema semi-intensivo, em viveiros. O desempenho das espécies foi diferenciado dependendo do sistema de cultivo: o tambaqui apresentou diferenças significativas no ganho em peso, sendo este 3,0 vezes maior no sistema semi-intensivo, enquanto o matrinxã não apresentou diferenças significativas no ganho em peso nos dois sistemas de cultivo. ABSTRACT -This study analyzed the influence of the fish farming system (intensive, in igarapé channel, or semi-intensive, in ponds) on the body composition of tambaqui, Colossoma macropomum, and matrinxã, Brycon cephalus, juveniles. Tambaqui (15.4 cm and 88.3 g average length and weight, respectively) and matrinxã (23.4 cm and 219.4 g average length and weight, respectively) were stocked at a density of 10 and 1 fish/m 2 in the intensive and semi-intensive culture system, respectively. Fish were fed to satiation, twice a day, a 30% crude protein comercial extruded feed, for 170 days. The proximate analysis of the edible portion (fillet) and the whole fish, at the end of the culture period, showed less fat deposition and higher protein retention for matrinxã and tambaqui raised in the intensive system. Weight gain was different between the two species, depending on the culture system: tambaqui showed significantly higher in weight gain when raised in the semi-intensive system, whereas matrinxã weight gain was not different in both culture systems.
ABSTRACT. Parasites in gills of farmed Brycon amazonicus (Characidae, Bryconinae) in stream channels of Turumã-Mirim, Amazonas State, Brazil. The purpose of the present study was to determine the prevalence and intensity of parasites in the gills as well as the condition factor of farmed Brycon amazonicus (Spix e Agassiz, 1829) from three stream channels in Tarumã-Mirim, Manaus, Amazonas State. Sanitary conditions of stream channels, fish handling, and water physiochemical parameters were monitored. From the 150 examined fish, 25.0% were contaminated by protozoan Ichthyophthirius multifiliis (18,0%) and by leeches Placobdella sp. (7.0%). The prevalence of I. multifiliis in the stream channels was of 22.0%, 18.0% and 14.0%, respectively, and the average intensity was high only in the stream channel that maintained fish in high population density. The leeches Placobdella sp. were found only in one stream channel. There was no seasonal variation in the infection by I. multifiliis; however Placobdella sp. infected the hosts only in January and March. Condition factor of parasitized fish was significantly lower (p < 0.001) than on unparasitized fish, but, it was not correlated with the parasites intensity.
RESUMO -Os organismos zooplanctônicos desempenham um importante papel na alimentação de larvas e pós-larvas de peixes, tanto na natureza, como em cativeiro em tanques de piscicultura. No aspecto do cultivo de zooplâncton cm massa, somente conhecendo-se os valores de alguns parâmetros importantes do ciclo de vida de um único indivíduo, em situações diversas, é que se pode avaliar se este estará respondendo de maneira adequada, ou não, a determinado tratamento aplicado. O trabalho mostra uma adaptação de mamadeiras plásticas comerciais para a utilização no estudo individualizado de microcrustáceos zooplanctônicos (cladóceros), em laboratório (aquários), viveiros de piscicultura, ou ambientes naturais (lagos e igarapés).Palavras-chave: Zooplâncton, Cladocera. estudos "in situ", Organismos-alimento, Piscicultura.Methodological Adaptation for Studies "In Situ" of Zooplanktonic Organisms, Applied to Fish Culture.ABSTRACT -Zooplanktonic organisms play an important role in the feeding of fish larvae, both in nature, and in artificial fish ponds. With the mass culture of zooplankton, the knowledge of important items of the organisms life cycle under different circumstances, can determine the success of the culture. This work shows an adaptation of commercial nursing bottles used in zc 'plankton studies that permits regular investigation of life cycle experiments of zooplanktonic ;rustaceans (Cladocera) in different environments such as: laboratory (immersed in aquariums or not) and "in situ", in fish ponds, or natural environments.
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